Process Research On The Green Synthesis Of Ethyl Carbamate

Ethyl Carbamate, an important chemical material, is widely used as intermediates in pesticides, pharmaceutical agents and so on. Phosgene and non-phosgene methods are the two main techniques for synthesizing it. However, because of green process, cheap material, urea alcoholysis method appealed more and more researchers.In this study, different amine absorbents, metallic oxides, initiates, supported catalysts were studied. The optimal synthetic conditions of Orthogonal experiment (zinc oxide as catalyst) are as follows:urea and ethanol in mole ratio1:12at180℃for3.5h, catalyst amount is0.5%, the rotate speed is200r/min and the yield of ethyl carbamate is82.41%.Zinc oxide-ferric oxide was also chosen as the catalyst for synthesizing Ethyl Carbamate. The optimal preparation conditions of the catalyst are as follows:Zn(NO3) and Fe(NO3)3in mole ratio2:0.8with feeding mode of parallel flow, roasting at300℃for5h. In this optimal conditions, the optimal synthetic conditions were:urea and ethanol in mole ratio1:14at170℃for3.5h, catalyst amount is0.5%, the rotate speed is200r/min and the yield of ethyl carbamate is88.79%.In this study, a self-designed apparatus for releasing amine was developed and the result shows that:without catalyst, the yield improved from35.68%to56.34%compared with the batch autoclave. So the byproduct amine decreased the yield and the key task is to eliminate the byproduct amine effectively.